Since its inception, biometric sensing technology has revolutionized identification and authentication processes. The ability to capture and store biometric data in a digital file of minimal size has yielded immense benefits in fields such as law enforcement, forensics, and information security.
However, the widespread adoption of biometric sensing technology in a broad range of applications has faced a number of obstacles. When biometric sensing technology is used for authentication (for example, for unlocking a mobile device), the process is inherently noisy or imperfect. For example, if the biometric sensor is a fingerprint sensor, it is possible that another person (i.e., an “imposter”) has a similar enough fingerprint to the fingerprint of the correct user so that the imposter is able to authenticate with his or her own fingerprint. This phenomenon is referred to as a “false acceptance.” The rate at which false acceptance occurs for a given authentication scheme is referred to as the “false acceptance rate” (FAR). The rate at which false rejection occurs for a given authentication scheme is referred to as the “false rejection rate” (FRR).
In one conventional approach for testing a biometric authentication system for security purposes, biometric samples are pre-collected from a large set of users and the collected data are subsequently run through the biometric authentication system as an offline test to evaluate FAR/FRR. The results from these FAR/FRR tests are used to operate the biometric authentication system at an acceptable FAR and FRR. In another conventional approach, a set of users are enrolled on the device, and repeated biometric samples are successively provided to measure actual false rejections as a function of how many times the biometric system rejects the user to login or authenticate with the system. This is frequently termed as “live testing.” One drawback of both database testing and live testing is that neither approach properly replicates the true interaction of the user with the biometric system in actual real world usage.